Monday, February 17, 2014

Live, Dry or Cured: Which Rock to Choose?

As a new hobbyist, the choices between different kinds of rocks can be overwhelming. Choosing the rock that is right for you is as important as choosing the size of the tank you want. Rock forms the basis of your aquascape, whether you intend to run a FOWLR (fish only with live rock) aquarium or a tank with abundant corals.

You have a choice between two basic types of rock: Dry and Live.

Live can further be categorized as cured live rock or uncured live rock. Curing is a process of eliminating dead and dying matter from live rocks. When rocks are shipped, there is usually a die off of animals and plants. As you know, decaying matter causes an ammonia spike. Placing this rock in an established tank could force another nitrogen cycle. This is the reason live rock should be used at the start of a tank or cured separately before adding to an established tank.

Now on to the different kinds of rocks available in the hobby.

AquaMaxx Dry Reef Rock
Dry Rock

As the name suggests, dry rock is clean, white, never used rock. Free of pests, hitchhikers or anything beneficial, dry rock is a popular starting point for most aquarists.

Dry rock can be man-made or quarried natural limestone. The rock is often porous and stackable, available in a variety of shapes and sizes and will not harm tank inhabitants. Another benefit is that is will not leech any undesirable contaminants into your tank.

Most dry rock is offered as "base rock" with the intent that a cured piece of live rock or bacterial supplement will jump start your nitrogen cycle and make the dry rock live in no time. Some popular sources of dry rock are AquaMaxx and CaribSea.

Fiji's Best Saltwater Aquarium Live Rock
Live Rock

Rock that has been previously seeded with beneficial bacteria is considered live rock. Typically seen as rocks with coralline algae, live rock can be used entirely for your aquascape or used sparingly to seed dry rock. Hitchhikers are common, both pests and beneficial, and serves to add a greater biodiversity to your tank.

The rock may go through a cycle in your tank, and it is recommended to cure it and test parameters before adding livestock to ensure that your tank has completed its nitrogen cycle.

One of the more popular choices for live rock is Fiji rock. Harvested as wild rock from the Fiji waters, this rock is porous and beautiful. Other varieties of live rock include Bali and Pukani rock. 

Real Reef Live Rock
Real Reef Rock

Why not get rock that is both live and is already the sought-after purple of every marine aquarist's dreams? Enter Real Reef Rock, a pigmented rock that is seeded with beneficial life forms and cured. The purple coloration of the rocks mimics coralline algae and immediately gives your tank the established look of an aged reef. Real Reef Rock is a man-made product.

Like with other live rock, you still might go through a cycle when adding this to your tank. It also comes with the same possibility of hitchhikers as Fiji rock although the seeding and curing process is done in a facility rather than in the wild as with Fiji Rock.

Uncured Live Rock
Uncured Rock

My personal favorite is uncured rock. This is rock that is picked fresh from the ocean, covered with coralline, sponges, mollusks, macros, pests and the best biodiversity you can add to your tank. You are almost guaranteed to have hitchhikers that you may not want. My most recent shipment of uncured rock had two mantis shrimp!

The rock was at the bottom of the ocean one day and in my tank on the second day. Even though the variety of encrusted corals and macros on this rock is amazing to me, only an advanced aquarist that knows how to deal with pests should consider uncured rock. This is not to say that new hobbyists should stay away, I certainly did not when I started reef tanks.

Uncured rock is also available cured, which just means it was given a chance to cycle in a holding tank before being shipped to you.

Whichever kind of rock you choose to add to your aquarium, planning ahead to get the most out of your aquascape is a good idea. Some great tips on the Fundamentals of Live Rock in Aquascaping can be found in this article by Mike Paletta.